1. Field of the Invention
The present invention relates to line-head control devices, image forming apparatuses, and line-head control methods.
2. Description of the Related Art
An image formed on a recording sheet by an image forming apparatus, such as a printing apparatus, can have variations in the magnification (a length from starting point of writing to an end point of writing) in the sub-scanning direction (sheet conveying direction). For instance, when a light emitting diode array (LEDA) is used as a line head that exposes an image carrier, mismatch between a light emission period of the LEDA and a linear velocity of a photosensitive element, or the like, can be a main cause of the magnification variation in the sub-scanning direction.
A technique for correcting the magnification variation in the sub-scanning direction by changing a light emission period of the LEDA is disclosed in, for instance, Japanese Patent Application Laid-open No. 2007-144731.
However, a conventional technique as that described above is disadvantageous in that an image density undesirably varies according to printing percentage of an image.